protected void btnLogin_Click(object sender, EventArgs e)
    {


        string Server = "10.0.103.19:389";
        string ruta = "LDAP://" + Server + "/CN=Users,DC=finuniversal,DC=Local";
        DirectoryEntry raiz = new DirectoryEntry(ruta);
        raiz.Path = ruta;
        raiz.AuthenticationType = AuthenticationTypes.Secure;
        raiz.Username = txtUsuario.Text;
        raiz.Password = txtContrasena.Text;

        string filtro = "sAMAccountName";
        string strSearch = filtro + "=" + txtUsuario.Text;
        DirectorySearcher dsSystem = new DirectorySearcher(raiz, strSearch);
        dsSystem.SearchScope = SearchScope.Subtree;
        try
        {
            Session["usuario"] = txtUsuario.Text;
            SearchResult srSystem = dsSystem.FindOne();
            Response.Redirect(Page.ResolveClientUrl("Panel.aspx"));

        }
        catch (Exception error)
        {
            ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "alertMessage", "alert('Verifique los Datos Correctos')", true);
            /*    Response.Write(error.Message);  */
        }

    }